Top, single ion confined in an RF Paul trap. Segmented d.c. electrodes (blue) provide confinement in the axial ( z ) direction. The RF electrodes (red) provide confinement in the radial ( x , y ) directions. A magnetic field gradient of ∂ B /∂ z = 22.41(1) T m −1 is applied along z . Doppler cooling and re-pump lasers at wavelengths of 369.52 and 935.18 nm, respectively, are indicated by the blue and orange beams. Transitions between the internal spin states are driven using an external microwave emitter. Electric field signals are applied to the ion through a d.c. end-cap electrode (E1) and are generated using an AWG that is capacitively coupled into the signal chain of E1. Bottom, zoom-in. An external electric field E applies a force F on the ion, resulting in a displacement δz . The transition frequency of the spin states is then shifted by Δ due to the magnetic field gradient.
